1. Field of the Invention
The present invention relates to an organic EL display device, and a method for manufacturing the organic EL display device, and more particularly to an organic EL display device and a method for manufacturing the same that allow light emitting elements which are self-emitting bodies arranged in respective pixels to emit light for display.
2. Description of the Related Art
In recent years, an image display device (hereinafter referred to as “organic EL (electro-luminescent) display device”) using self-emitting bodies called “organic light emitting diodes (OLED)” has been put into a practical use. As compared with a liquid crystal display device in a related art, the organic EL display device uses the self-emitting bodies, and therefore not only is excellent in visibility and response speed, but also does not require an auxiliary lighting device such as backlight. As a result, the organic EL display device can be further thinned.
In a so-called “top emission type display device” in which a light is emitted on a side of an insulating substrate where light emitting elements are formed, in an upper electrode and a lower electrode which are two electrodes that sandwich an organic layer having at least one light emitting layer therebetween, the upper electrode is an electrode that covers the respective pixels in a display area on which the organic layer is formed, and made of a transparent conductive material. It is desirable to more thin the upper electrode for the purpose of improving the transmittance of light. However, a resistance value increases more as the upper electrode is thinner, resulting in a voltage drop. As a result, uneven brightness is likely to be generated in an end and a center of the display area.
JP 2004-207217 A discloses that the upper electrode is brought into contact with an auxiliary electrode of the same layer as that of the lower electrode within the display area through a contact hole to decrease a resistance of the upper electrode. JP 2011-221203 A discloses that the upper electrode is electrically connected to a conductive substrate through the connection hole within the display area.